Catalog Displays Retrieval and FAST May 31 2005

Catalog Displays, Retrieval, and FAST May 31, 2005 1

Overview Online Catalog Interfaces and Subject Searching n FAST: Faceted Application of Subject Terminology n 2

Subject Searching in OPACs: Problem Statement n Subject access can be provided via: n Controlled vocabulary • But users must discover the authoritative terms themselves • Interfaces that assist users are more effective than those that do not n Natural language • User must consider word forms, synonyms and homographs in constructing searches 3

Subject Searching in OPACs: Solutions Authority control of subject terms n Free text searching conventions (truncation, Boolean logic, proximity searching) n Browsing n Search facilitation n 4

Authority control of subject terms UF (4 xx) or SA, NT, BT (5 xx) references direct users to authoritative or related headings n Scope notes may also be displayed n Authority control works! n n Wilkes & Nelson (1995): 75% of failed searches in catalog without authority control would have been successful with authority control 5

Authority control of subject terms (cont. ) Should catalogs direct users to the correct form of headings? Or n Should catalogs display the appropriate entries directly? n 6

Authority control of subject terms (cont. ) n n Problem: Users may not use the terms in the controlled vocabulary Solutions: 1. 2. Provide bibliographic instruction in subject searching Make LCSH (or other thesaurus) available in paper or electronically 7

Free Text Searching n Truncation User must consider all possible completions to a partial word entry Example 1: librari? will retrieve librarians and librarianship, but miss library Example 2: cat? will retrieve both cat and cats (desired result), but also catapult and caterpillar n 8

Free Text Searching (cont. ) n Boolean logic Use of Boolean operators AND, OR, NOT n Users need to understand how to use operators n Users need to know what is in the database Example: Castles AND movies might retrieve works on Irene and Vern Castle (American dancers) n Research demonstrates that most users have difficulty constructing effective Boolean searches n Also, some catalogs do not explicitly inform users about default operators n n Works best with instruction (online or training sessions) 9

Free Text Searching (cont. ) n Proximity searching n n Can specify word order, words next to each other, words within a prescribed number of words of each other Problems with free-text searching even with these techniques Lack of context n Cannot account easily foreign languages n 10

Browsing n n Definition: Browsing is an exploration of a database with the idea that something interesting or useful might be encountered following connections. (Olson and Boll) Browsers can sometimes identify a specific purpose n Some area(s) of interest begin(s) the search 11

Browsing Pre-automation: browse in the shelflist Or n find one or two items of interest in the catalog, then continue the search at the shelf n n n Post-automation: browse an online shelflist Surfing the web is a type of browsing activity! 12

Search Facilitation n n Sophisticated search capabilities (such as Boolean searching) are not used Help screens and screens with lists of commands are also not heavily used n Require the user to go to the help screens or interpret the information 13

Search Facilitation (cont. ) Spell checkers n Allow users to browse the classification scheme if captions are included with class numbers n Tree structures based on subject headings n 14

FAST: Faceted Application of Subject Terminology n n LCSH is widely used and has been basis of numerous other thesauri around the world Its application (constructing headings) requires significant training FAST is an attempt to simplify the process of assigning subject headings, but still use LCSH’s rich vocabulary FAST is compatible with LCSH – can convert from LCSH to FAST 15

FAST Design n n Be usable by people with minimal training and experience, Enable a broad range of users to assign subject terminology to Web resources, Be amenable to automated authority control, Be compatible with use as embedded metadata, Focus on making use of LCSH as a post-coordinate system in an online environment. 16

FAST Facets n Six facets: Topical n Geographic n Form n Period n Personal names n Corporate names n 17

Examples n Each facet is assigned in its own MARC field: Blacksmithing $x Equipment and supplies California $z Los Angeles $z Hollywood $v Controversial literature $v Early works to 1800 1900 -1999 18

Conversion of existing headings 650 0 Authority files (Information retrieval) $z Italy $z Florence $v Congresses. Converts to: Authority files (Information retrieval) § Italy $z Florence Congresses 19

Additional Simplification Characteristics n n Authority file permanently retains all authority records Authority records are designated “obsolete” rather than removed from the database n n n Supports the linked structure of the file All FAST records will be linked back to the LC authority record from which it was derived using 7 xx linking fields. Ongoing OCLC project: will hear more in the future 20